How is energy produced during aerobic respiration?

Energy during aerobic respiration is produced primarily by converting glucose in the presence of oxygen. This process involves a series of metabolic steps known as glycolysis, the Krebs cycle, and oxidative phosphorylation.

Initially, glucose is broken down in glycolysis, which occurs in the cytoplasm of the cell, resulting in a smaller molecule called pyruvate. This pyruvate then enters the mitochondria, where it undergoes further processing in the Krebs cycle, producing electron carriers such as NADH and FADH2. These carriers then donate electrons to the electron transport chain, which takes place in the inner mitochondrial membrane. Here, the energy released from the electron transfers is used to pump protons across the membrane, creating a proton gradient. This gradient ultimately drives ATP synthase to produce ATP, the energy currency of the cell, as protons flow back into the mitochondrial matrix.

In summary, the conversion of glucose in the presence of oxygen is critical because it facilitates the complete oxidation of glucose, allowing for maximum ATP yield compared to anaerobic respiration, which occurs without oxygen and results in less energy being produced.